The present invention relates to a method for processing audio signal, and more particularly to a method and apparatus of encoding and decoding audio signal.
The storage and replaying of audio signals has been accomplished in different ways in the past. For example, music and speech have been recorded and preserved by phonographic technology (e.g., record players), magnetic technology (e.g., cassette tapes), and digital technology (e.g., compact discs). As audio storage technology progresses, many challenges need to be overcome to optimize the quality and storability of audio signals.
For the archiving and broadband transmission of music signals, lossless reconstruction is becoming a more important feature than high efficiency in compression by means of perceptual coding as defined in MPEG standards such as MP3 or AAC. Although DVD audio and Super CD Audio include proprietary lossless compression schemes, there is a demand for an open and general compression scheme among content-holders and broadcasters. In response to this demand, a new lossless coding scheme has been considered as an extension to the MPEG-4 Audio standard. Lossless audio coding permits the compression of digital audio data without any loss in quality due to a perfect reconstruction of the original signal.
In one embodiment, the method includes receiving an audio data frame having at least first and second channels. The first and second channels have been independently subdivided into blocks if the first and second channels are not correlated with each other, and the first and second channels have been synchronously subdivided into blocks if the first and second channels are correlated with each other and difference coding is used. The embodiment further includes obtaining subdivision information from the audio data frame. The subdivision information includes first information and second information. The first information indicates whether the first and second channels are independently subdivided or synchronously subdivided, and the second information indicates how the subdividing is performed. The first and second channels are decoded based on the obtained subdivision information.